title: Perivascular adipose tissue-derived visfatin is a vascular smooth muscle cell growth factor: role of nicotinamide mononucleotide.
abstract: OBJECTIVE
  Perivascular adipose tissue (PVAT) inhibits vascular smooth muscle cell (VSMC) contraction and stimulates VSMC proliferation by releasing protein factors. The present study was to determine whether visfatin is involved in these paracrine actions of PVAT, and if so, to explore the underlying mechanisms.
  
  
  RESULTS
  Visfatin was preferentially expressed in Sprague-Dawley rat and monkey aortic PVAT, compared with subcutaneous and visceral adipose tissues. The PVAT-derived visfatin was found to be a VSMC growth factor rather than a VSMC relaxing factor, which was proved by visfatin-specific antibody/inhibitor and direct observation of recombinant visfatin. Exogenous visfatin stimulated VSMC proliferation in a dose- and time-dependent manner via extracellular signal-regulated kinase (ERK 1/2) and p38 signalling pathways. This proliferative effect was further confirmed by enhancement of DNA synthesis and upregulation of proliferative marker Ki-67. Visfatin had no anti-apoptotic effect on normal cultured VSMCs, and it exerted an anti-apoptotic effect only during cell apoptosis induced by H2O2, excluding a role of anti-apoptosis in the visfatin-induced VSMC proliferation. Insulin receptor knockdown did not show any action on the visfatin effect. However, visfatin acted as a nicotinamide phosphoribosyltransferase to biosynthesize nicotinamide mononucleotide (NMN), which mediated proliferative signalling pathways and cell proliferation similar to the visfatin effect.
  
  
  CONCLUSIONS
  Visfatin stimulates VSMC proliferation via NMN-mediated ERK1/2 and p38 signalling. The present study provides a molecular link of visfatin to the paracrine action of PVAT, demonstrates a novel function of visfatin in promoting VSMC proliferation, and reveals NMN as a novel signalling molecule that triggers the proliferative process.
authors.affiliation: Department of Pharmacology, Second Military Medical University, 325 Guo He Road, Shanghai 200433, People's Republic of China.
authors.forename: Pei
authors.initials: P
authors.lastname: Wang
authors.forename: Tian-Ying
authors.initials: TY
authors.lastname: Xu
authors.forename: Yun-Feng
authors.initials: YF
authors.lastname: Guan
authors.forename: Ding-Feng
authors.initials: DF
authors.lastname: Su
authors.forename: Guo-Rong
authors.initials: GR
authors.lastname: Fan
authors.forename: Chao-Yu
authors.initials: CY
authors.lastname: Miao
mesh_terms: D000273:Adipose Tissue / Q000378:metabolism; D000818:Animals; D049109:Cell Proliferation; D048049:Extracellular Signal-Regulated MAP Kinases / Q000502:physiology; D019394:Ki-67 Antigen / Q000032:analysis; D020935:MAP Kinase Signaling System; D008297:Male; D051379:Mice; D008813:Mice, Inbred ICR; D009131:Muscle, Smooth, Vascular / Q000166:cytology*; D032389:Myocytes, Smooth Muscle / Q000166:cytology*; D009537:Nicotinamide Mononucleotide / Q000502:physiology*; D054409:Nicotinamide Phosphoribosyltransferase / Q000235:genetics / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D011972:Receptor, Insulin / Q000502:physiology; D048051:p38 Mitogen-Activated Protein Kinases / Q000502:physiology
chemical_list: D019394:Ki-67 Antigen; D009537:Nicotinamide Mononucleotide; D054409:Nicotinamide Phosphoribosyltransferase; D011972:Receptor, Insulin; D048049:Extracellular Signal-Regulated MAP Kinases; D048051:p38 Mitogen-Activated Protein Kinases